There have been a number of machines developed which are designed to accept fibrous feed stock, and to act thereupon to compress it and produce highly compacted pellets or cubes. Commonly called cubing machines, machines of the general type to which this invention relates are shown in U.S. Pat. Nos. 3,279,396; 3,354,844; 3,363,587; and 3,407,756. Cubing machines of this general type have an annular die assembly that is clamped between mounting plates, and which has a plurality of equally spaced die openings extending radially therethrough. A circular die cavity or track is formed on the inner periphery of the annular die assembly, and a circular press wheel having a diameter substantially smaller than the inner diameter of the annular die assembly is mounted eccentrically on a rotating bracket and rides in the track; sometimes, a plurality of such press wheels are utilized, usually spaced evenly about the central axis of the annular die assembly. A drum auger is arranged to extend concentrically about the central axis of the annular die assembly from one side of the assembly, thereof, and is mounted within a housing that may carry one or more mating auger flights on its interior. The drum auger functions to accept feed stock from an intake hopper or the like, and to deposit it into the circular die cavity or track ahead of the rotating press wheel. The press wheel compresses the feed stock into the circular die cavity or track, and forces it under pressure through the die openings to produce an extrusion that is then broken into pieces to form pellets or cubes.
The auger flight carried on the drum auger is typically constructed of a helically or spirally-arranged metallic blade that is welded on the outer surface of a cylindrical drum, to produce the flight. The forward tip of this auger blade, that is, the end thereof adjacent to the circular die cavity or track, is perhaps the most critical element of the auger because its function is to directly deposit the feed stock into the cavity. Usually, the auger blade tip will be tapered downwardly to a minimum height at its outer end, and sometimes it will be provided with a replaceable metallic wear plate required because extensive tip wear is common in a cubing machine. The typical rigid metallic tip of an auger blade is spaced a substantial distance from the press wheel and the die assembly, and is shaped to provide considerable clearance so that jamming of the feed stock and consequent possible damage to the machine will be avoided by providing a relatively large space through which feed stock can flow if an excessive accumulation occurs.
While providing space between the auger tip, the annular die assembly and the press wheel will usually solve the jamming or plugging problem, it also normally allows a considerable amount of feed stock to unnecessarily escape from in front of the press wheel as the latter is rotated around the circular die cavity or track. This in turn reduces the efficiency of the cubing machine over what might otherwise be possible, and functions to allow feed stock to escape even when the stock is sufficiently dry and of a characteristic that jamming or plugging of the equipment is not likely to occur.
There is thus need for an improved feed auger tip arrangement for a cubing machine, one that will increase the supply of feed stock deposited in the circular die cavity in front of the press wheel of the machine under normal circumstances, but which will still allow feed stock to escape from the die cavity or track when necessary so that jamming or plugging of the equipment will not occur. The present invention is intended to satisfy that need.